74 
BULLETIN" 824, TJ. S. DEPARTMENT OF AGRICULTURE. 
Table 45. — Summary of investigations on active insecticidal principle of Pyrethrum — 
Continued. 
Year. 
Investigator. 
Bibliog- 
raphy 
reference. 
Species of Pyrethrum 
used. 
Active principle considered 
to be— 
1879 
1881 
1889 
1889- 
1894 
1890 
1890 
1890 
1890 
1895 
1897 
1S98 
1905 
1907 
1909 
1909 
1912 
1915 
Dal Sie. 
Textor. 
Gillette. 
►Zuco . 
Hirscbsobn 
Eymard 
Schlagdenhauflen and 
Reeb. 
Thorns 
De Boisse 
Durrant 
Gerard 
60 
272 
96 
1/296, 297, 
I 298,299 
133 
77 
245 
275 
64 
73 
93 
>SatO» ! 236,237 
Eujitani 
Reeb 
Yoshimura and Trier 
Siedler 
214 
295 
25S 
(?) A free volatile acid. 
(?) A soft resin. 
(?) j Soluble in ether. 
i (Isolated a paraffin, a phytostercl, 
[CinerarisefoHum \\ an alkaloid, and a glucosicle, 
but all were inert. 
Roseum (?) 
(?) 
CinerarisfoJiu m , 
Not acid and not volatile. 
Principally a resin. 
" Pyrethrotoxic acid.'' 
. .do I An essential oil. 
..do I A resin. 
. .do I A resin and volatile oil. 
. .do. j An oleoresin and volatile oil. 
..do.. A sirupy resin, "pyretol." 
..do An ester, "pyrethron." 
Pyrethrotoxic acid. 
Cholin and staehydrin (inert). 
Nothing definite. 
EXPERIMENTAL WORK. 
Preliminary Tests. 
The coarsely powdered flowers, subjected to steam distillation, 
yielded 0.28 per cent of a fragrant oil. This had an odor somewhat 
like that of rosemary oil, together with a characteristic Pyrethrum 
odor, but the amount obtained was too small to permit a chemical 
examination. Tested against flies, this oil had only slight repelling 
properties, and did not show the characteristic effects of Pyrethrum 
powder. 
A steam distillation of the flowers in the presence of sodium 
hydroxid yielded only 0.1 5 per cent of oil, which had a disagreeable 
odor. Careful tests for alkaloids in the distillate gave negative 
results. A steam distillation of the flowers in the presence of a 
little sulphuric acid yielded 0.16 per cent oil, which lacked the 
characteristic odor of Pyrethrum. Tested against flies, the oils 
from the alkaline and acid steam distillations had even less effect 
than that obtained in a straight steam distillation. From these 
distillation experiments it may be concluded that the substance, or 
substances, in Pyrethrum which cause its characteristic effect upon 
insects are not removed by steam distillation in neutral, alkaline, 
or acid solutions. 
After being subjected to steam distillation in neutral solution, the 
flowers were dried and tested upon roaches, when they were found to 
be as active as before treatment. This shows that treatment with 
steam does not decompose the insecticidal principle. 
To test the action of dilute acid and alkaline solutions upon 
insect flowers, 50 grams of the coarsely powdered material were 
treated with 500 cc. of solution for 24 hours, stirred occasionally, 
